1. Field of the Invention
The present invention relates generally to searching wide area computer networks for information, and more particularly to searching the World Wide Web for topical information.
2. Description of the Related Art
The wide area computer network known as the “World Wide Web”, or simply “Web”, contains a vast amount of information in the form of Web pages. Each Web page is electronically stored in a respective Web site on a computer, referred to as a Web server, with the Web itself including many Web servers that are interconnected by means of the Internet. A person can connect a computer to the Internet via, e.g., a telephone line, and thereby electronically access the Web pages on the Web servers.
As the Web has grown, many millions of Web pages have been created. In other words, the Web contains a vast amount of information, and the content of the Web grows and changes minute by minute. It will accordingly be appreciated that some means must be provided for a person to sort through the vast quantities of Web pages to find a particular item of interest.
With the above consideration in mind, most users employ software known as Web browsers when accessing the Web. To search the Web for a particular topic of information, the user causes their Web browser to access a Web site of a centralized search engine that is maintained by a search company. Examples of currently popular search engines are Alta Vista™ and Hotbot™.
Centralized search engines use software referred to as “crawlers” to continuously access Web pages and log and categorize the pages in a centralized index. When a person wishes to retrieve information, the person's browser accesses a centralized search engine using a query, for example. “luxury cars”. In response, software at the centralized engine accesses its index to retrieve names of Web sites considered by the search engine to be appropriate sources for the sought-after information. The search engine transmits to the browser hyperlinks to the retrieved sites, along with brief summaries of each site, with the browser presenting the information to the user. The user can then select the site or sites they want by causing the browser to access the site or sites.
Owing to the burgeoning of the Web and the ever-growing amount of its information, and the fact that the above-described centralized crawler schemes posture themselves to respond to any possible query (i.e., to be all things to all people), centralized crawler/searchers require large investments in hardware and software and must never cease crawling the Web, to index new pages and to periodically revisit old pages that might have changed. Indeed, one Web search company currently requires the use of 16 of the most powerful computers made by a major computer manufacturer, each computer having 8 gigabytes of memory. Another search company currently uses a cluster of 300 powerful workstations and over one terabyte of memory to crawl over 10 million Web pages per day. Despite these heroic efforts, however, it is estimated that a single search company is able to index only 30%-40% of the Web, owing to the size of the Web which, incidentally, shows no signs of slowing its rate of expansion.
Accordingly, one problem with current technology that is recognized and addressed by the present invention is the need to reduce the vast amount of Web search hardware and software that is inherently required by a centralized search scheme.
Additionally, evaluating whether a particular Web page contains relevant information with respect to a user query is sometimes difficult. Moreover, user queries may not be effectively articulated, or they may be overbroad. Consequently, a Web search engine frequently responds to a query by returning a large number of Web pages that are of little or no interest to the requester. Nonetheless, a user must laboriously sort through hundreds and perhaps thousands of returned Web pages, which, as discussed above, can be considered to represent only 30%-40% of the total Web content in any case. Moreover, because a centralized crawler seeks the capability to respond to any query, most of the index of any single centralized system contains information that is of little or no value to any single user or indeed to any single interrelated group of users.
Thus, two other problems recognized and addressed by the present invention are the lack of focus of search results, and the fact that centralized crawlers are not tailored to any particular user or to any particular interrelated group of users and, thus, contain mostly irrelevant information, from the point of view of a single user or group of users.
In addition to the above considerations, the present invention recognizes that many if not most Web pages refer to other Web pages by means of hyperlinks, which a user can select to move from a source Web page to a target Web page. The present invention further recognizes that such hyperlinks are more than simply navigation tools; they are important categorization tools as well. More specifically, a particularly “good” page on a certain topic might be referred to by a large number of other pages, and thus the number of referrals (referred to as “inlinks”) to a Web page is an indication of its effectiveness.
It happens that with the existing Web communication protocol (hypertext transfer protocol, or “http”), when a user clicks on a hyperlink to a target Web page v from a source Web page u, the user's browser sends the identity of the source Web page u to the Web server that hosts the target Web page v, and this information can be recorded or logged. Unfortunately, current logs of which Web pages refer to which other Web pages are mostly unused and indeed mostly not enabled by Web site managers, and the logs moreover consume a relatively large amount of electronic data storage space. Also, no standard way exists for a remote user to access and use the information in the logs.
The present invention, however, recognizes the above-noted problem and addresses how to exploit this currently unused but potentially valuable information in the context of resolving the unfocussed, centralized crawling problems noted above.